package com.education.util;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

/**
 * Created by Fan307 on 2016/11/9.
 */
public class MakeCertPic {

    //验证码图片中可以出现的字符集，可以根据需要修改
    private char mapTable[]={
            'a','b','c','d','e','f',
            'g','h','i','j','k','l',
            'm','n','o','p','q','r',
            's','t','u','v','w','x',
            'y','z','0','1','2','3',
            '4','5','6','7','8','9'
    };
    /* 功能：生成彩色验证码图片
     参数wedth为生成图片的宽度，参数height为生成图片的高度，参数os为页面的输出流
    */
    public String getCertPic(int width,int height,OutputStream os){
        if(width<=0)
            width=60;
        if(height<=0)
            height=20;
        BufferedImage image= new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
        //获取图形上下文
        Graphics g = image.getGraphics();
        //设定背景颜色
        g.setColor(new Color(0xDCDCDC));
        g.fillRect(0,0,width,height);
        //画边框
        g.setColor(Color.black);
        g.drawRect(0,0,width-1,height-1);
        //随机产生的验证码
        String strEnsure = "";
        //4代表4为验证码，如果要产生更多位的验证码，则加大数值
        for(int i = 0;i<4;++i){
            strEnsure += mapTable[(int) (mapTable.length*Math.random())];
        }
        //将认证码显示到图像中，如果要生成更多位的验证码，增加drawString语句
        g.setColor(Color.black);
        g.setFont(new Font("Atlantic Inline",Font.PLAIN,18));
        String str = strEnsure.substring(0,1);
        g.drawString(str,8,17);
        str = strEnsure.substring(1,2);
        g.drawString(str, 20, 15);
        str = strEnsure.substring(2,3);
        g.drawString(str, 35, 18);
        str = strEnsure.substring(3,4);
        g.drawString(str, 45, 15);
        //随机产生15个干扰点
        Random rand = new Random();
        for(int i=0; i<10; i++){
            int x = rand.nextInt(width);
            int y = rand.nextInt(height);
            g.drawOval(x,y,1,1);
        }
        //释放图形上下文
        g.dispose();
        try{
            //输出图形到页面
            ImageIO.write(image, "JPEG", os);

        }catch (IOException e){
            return "";
        }
        return strEnsure;
    }
}
